Method of cooling damaged blast furnace cooling elements



J. E. ALLEN March 10, 1970 METHOD OF COOLING DAMAGED BLAST FURNACE COOLING ELEMENTS 2. Sheets-Sheet 1 WU QM mh r N MA March 10, 1970 J. E. ALLEN 3,499,638

METHOD OF COOLING DAMAGED BLAST FURNACE COOLING ELEMENTS- Filed Nov. 13, 1967 2 Sheets-Sheet 2 Fizz 62.7 507. Jfizffifem.

United States Patent 3 499 638 METHOD OF COOlJN G DAMAGED BLAST FURNACE COOLING ELEMENTS John E. Allen, 606 Timber Lane, Lake Forest, Ill. 60045 Filed Nov. 13, 1967, Ser. No. 682,135 Int. Cl. C21b 7/16; C21c 5/48; F25d 31/00 US. Cl. 26641 6 Claims ABSTRACT OF THE DISCLOSURE The present method for the emergency cooling of furnace elements such as tuyeres and the like employs a high presure gas which is inert to the metallurgical process involved. Should the furnace element become damaged during operation, the flow of cooling water to the element is shut off and the high pressure gas is delivered to the element for release within the element. The resulting expansion of the gas produces the desired cooling effect.

The invention relates to the emergency cooling of certain furnace cooling elements and has reference more particularly to a method of using a high pressure inert gas in a manner whereby the same becomes a refrigerant for cooling damaged blast furnace elements so as to maintain their effectiveness until they can be repaired or replaced.

Blast furnace elements such as cinder notches, tuyeres, bosh, stack and hearth cooling elements are cooled by circulating water, generally at a higher pressure than that existing within the furnace, through the units which are connected by piping either singly or in groups as the demand may be. Due to wear and operating irregularities in the smelting process and also accidents of various types, such elements are subject to frequent and serious damage. When damage does occur the Water circulating through the section leaks into the furnace or into the brick lining of the furnace since the element-s essentially consist of hollow copper castings or cast iron sections. The leaking water may cause local cooling of the process to such an extent that an emergency shutdown becomes necessary.

When a cooling element such as described becomes damaged, present emergency procedures consist in isolating the damaged unit by reducing the water flow to the point where pressure of the vgas in the furnace is higher than that of the Water pressure. Other emergency measures may be employed since each different cooling element requires diiferent treatment. However, maintenance of the production schedule is a major financial consideration. Hence, when shutdowns do occur they should be Well planned and scheduled to complete all work in the most expeditious and precise manner.

The present invention contemplates a method and apparatus for the emergency cooling of damaged cooling elements so as to maintain their eflectiveness until a planned shutdown of the furnace can be arranged.

Ano her and more specific object of the invention is to provide an improved method for the emergency cooling of damaged furnace elements wherein an inert gas under hight pressure is delivered to the damaged element where it expands and becomes a refrigerant for cooling the element.

With these and various other objects in view, the invention may consist of certain novel features of construction and ope-ration as will be more fully described and particularly pointed out in the specification, drawings and claims appended thereto.

In the drawings which illustrate an embodiment of the device and wherein like reference characters are used to design-ate like parts:

FIGURE 1 is a sectional view showing a blast furnace cooling element such as a'tuyere and which is equipped with apparatus for emergency cooling in accordance with the invention should the tuyere become damaged.

FIGURE 2 is an end view taken exteriorly of the furnace looking towards the tuyere and which illustrates the piping for water cooling the element and also the gas piping for emergency cooling all as shown in FIGURE 1; and

FIGURE 3,is a sectional view similar to FIGURE 1 but showing a damaged blast furnace tuyere.

The drawings show the invention 'as applied to a blast furnace tuyere identified in its entirety by the numeral 12 and which is typical of the furnace cooling elements to which the invention may be applied. The tuyere cooler 10 is located in the wall I I of a blast furnace or the like and the tuyere comprises the projecting nozzle portion 12, the anchored body portion 13 and the tuyere holder 14. The nozzle portion of the tuyere and also the body portion are formed of metal castings, the nozzle having an inside wall 15 and an outside wall 16 whereas the body portion includes inside and outside walls 17 and 18, respectively.

The space between the walls '15 and 16 of the nozzle is cylindrical and annular as is also the space between the walls 17 and 18 of the body portion. The interior spaces receive a continuous fiowof cooling water during opera tion of the furnace to maintain the elements at a relatively low temperature. For this purpose the Water circulating pipes 20 and 21 are connected to the nozzle portion and similar water circulating pipes 22 and 23 are connected to the body portion. Pipe 20 supplies cooling 'water to the annular space of the nozzle and after it has circulated in said space the water exits by Way of the pipe 21. The pipe 22 supplies cooling Water to the space formed by the inside and outside walls of the body portion and said Water is discharged from the space by the pipe 23. Hand operated valves 24 and 25 are located in the pipes 20v and 21, respectively, so that the cooling water can be shut off or reduced to the extent desired in the event of damage to the nozzle of the tuyere. The pipes 22 and 23 are likewise equipped with hand operated valves 26 and 27, respectively, for a similar purpose.

In accordance with the invention a high pressure gas is delivered to the tuyere should damage to the element occur and in such cases this requires that the cooling water be shut ofi. The gas is inert to the metallurgical process involved and may comprise nitrogen gas, carbon dioxide or the like, and which is supplied to the nozzle and body portions of the tuyere in the place of the water. The gas will expand within the annular interior spaces and the same will produce a cooling effect to prevent further damage to the element, and this is accomplished without disturbing the efliciency of the metallurgical process.

The compressor-receiver unit for the gas is indicated by the numeral 28 and the delivery line for the compressed gas is indicated by the numeral 30. This high pressure gas delivery line has a branch pipe 31 which is connected to the pressure tank 32. A second branch line 33 is connected at 34 to the nozzle 12 of the tuyere, and a third branch line 35 is connected at 36 to the body portion of the tuyere. A hand operated valve 37 is located in line 30 adjacent the compressor and hand operated valves 38, 40 and 41 are located in the branch lines, respectively. Following expansion of the gas within the interior spaces of the tuyere, the gas is returned by the line 44. This line has connection wtih the exit water pipe 23 immediately in advance of valve 27 and the said gas return line is equipped with the hand operated valve 45. A branch line 3 46 joins the exit Water line 21 with the gas return line 44 and this branch of the gas return line is equipped with a hand operated valve 47. The line 44 delivers the hot expanded gas to a heat exchanger 50 and from the exchanger the gas is returned by line 51 to the compressor-receiver unit 28 to be compressed and recirculated.

When a tuyere or other cooling unit of a metallurgical furnace is damaged during operation as illustrated, for example, in FIGURE 3, the unit is isolated as heretofore by shutting off the cooling water. This requires the closing of valves 24, 25, 26 and 27. In the place of the cooling water, a flow of high pressure inert gas is delivered to the damaged tuyeres by the opening of the valves 40, 41 and 45 and 47. Due to the expansion of the high pressure gas released within the annular spaces of the tuyere, the gas performs a cooling function and maintains the damaged tuyere at a relatively low safe temperature. Some of the high pressure gas will exit from the damaged end of the nozzle and here again, its release and expansion will accomplish a further cooling at the point of damage.

The cost of producing or providing the compressed inert gases for emergency cooling is high in comparison to the cost of supplying cooling Water, but the same is insignificant to the cost of an emergency shutdown. In addition it is preferred to have an inert gas issue from the damaged end of the nozzle in place of water, since the gas has little, if any, effect on the metallurgical processes that may be involved. When a gas issues from the internal space of the nozzle or from the internal space of the body portion by reason of a break in the wall, the hot gases from the furnace are prevented from entering, and this feature also assists in preventing further damage until a planned shutdown of the furnace takes place.

What is claimed is:

1. In a method of cooling damaged cooling elements of a metallurgical furnace to maintain their effectiveness during continued operation of the furnace, the steps which include shutting off the flow of cooling water to the element following damage to the same, and supplying a gas to the damaged element which is inert to the metallurgical process involved and at a relatively high pressure, whereby said high pressure gas expands upon being released within the damaged element and produces a cooling elfect upon the element.

2, A method of cooling damaged cooling elements of a metallurgical furnace as defined by claim 1, wherein the inert high pressure gas is selected from the group consisting of nitrogen, carbon dioxide and blast furnace gas.

3. A method of cooling damaged cooling elements of a metallurgical furnace as defined by claim 1, wherein the damaged element comprises a blast furnace tuyere and wherein the inert high pressure gas is one of the group consisting of nitrogen, carbon dioxide and blast furnace gas.

4. In a method of cooling damaged cooling elements of a metallurgical furnace to maintain their effectiveness during continued operation of the furnace, the steps which include closing the valves on the supply and exit pipes of the system which supplies the cooling water to the interior spaces of the damaged element, thereby shutting off the flow of cooling water to said interior spaces, and then opening the valves on the high pressure gas line system to supply a gas to the interior spaces which is inert to the metallurgical process involved and at a relatively high pressure, whereby the high pressure gas expands upon being released Within the damaged element and produces a cooling efifect upon the element.

5. A method of cooling damaged cooling elements of a metallurgical furnace as defined by claim 4, wherein the inert high pressure gas is selected from the group consisting of nitrogen, carbon dioxide, and blast furnace gas.

6. A method of cooling damaged cooling elements of a metallurgical furnace as defined by claim 4, wherein the damaged element comprises a blast furnace tuyere and wherein the inert high pressure gas is selected from the group consisting of nitrogen, carbon dioxide, and blast furnace gas.

References Cited UNITED STATES PATENTS 2,310,698 2/1943 Hulton 263-44 2,337,008 12/1943 Vinther 62--259 X 2,799,493 7/1957 Brownell et al. 266-32 J. SPENCER OVERHOLSER, Primary Examiner JOHN S. BROWN, Assistant Examiner US. Cl. X.R. 62-62, 259 

